Cs-Cart Payway Gateway Does Not Work

I have recently noticed that the PayWay payment gateway that comes with default CS-Cart has does not work correctly. Payments are processed however they are marked as Incomplete in the order status and an email notification of the order is not sent. A payment notification is sent though but not the CS-Cart order. All other payment types work ok.

I almost sent out a large order that hadn't been paid

CS-Cart: v4.11.3
PHP: 7.3.13
Dedicated server

I have tried to look into this and whilst CS-Cart supports php v7.2, PayWay doesn't so the PayWay payment processor that is included in CS-Cart will not work:

NOTE: Payway doesn't yet support the removal of mcrypt in php 7.2, so you'll need php 7.1 or lower for this to work.

I have other web sites on my server that have many features requiring php v7.2 and above so they would be held back because of CS-Cart.

This needs to be URGENTLY FIXED otherwise CS-Cart software is of no use to anyone that wants to use CS-CART with PayWay even though CS-CART says it will

You can specify what php version to use via the htaccess file.

Thanks, what line would I put in the file

AddHandler application/x-httpd-php71 .php .php5 .php4 .php3

Usually php version can be also switched in the control panel of the server

Thanks, I spoke to my server admin guy and he says that as I am running nginx I had to switch the whole server to a different php version. He switched it to v7.1 and the default CS-Cart PayWay module still doesn't work. I spoke to PayWay and they have advised that there is nothing different on their end so it is isolated to the fact the CS-Cart are including a payment gateway in their default version that doesn't work...unless someone else out there that is using PayWay can advise different.

I have been met with complete silence from CS-Cart in their bug tracker

Look for errors in Admin logs related to PayWay.

There isn't any error entries pointing to PayWay...in fact no errors are listed just order creates, status changes etc

If http requests is enabled in log settings you should see requests and responses for Payway. That's where you would see the errors.